1. Microscopes
How can we observe cells?

2. What technology allows biologists to study microscopic life?
A. Compound Light Microscope
Has two lenses – ocular (eyepiece) and objective
In order to be viewed, specimen must be thin (so the light may shine through the specimen) and placed on a slide.
Specimen may be stained to better see structures

3. Fill It In …
Label the ocular lens and the objective lens:

4. Ocular lens (Eyepiece)
Body Tube
Nosepiece
Arm
Objectives
Stage
Stage Clips
Coarse Adjustment
Diaphragm
Fine Adjustment
Light
Always carry a microscope with one hand holding the arm and one hand under the base.
Base

5. What technology allows biologists to study microscopic life?
B. Electron Microscope
Uses electrons to produce an image
Types:
Scanning Electron Microscope (SEM)
Electrons scan the surface of a specimen
Produces a 3-D image

6. What technology allows biologists to study microscopic life?
B. Electron Microscope
Transmission Electron Microscope (TEM)
Designed to look at structures inside a cell
Capable of greatest magnification

8. What technology allows biologists to study microscopic life?
C. Limitations of microscopes
Magnification is limited by the strength of the lens.
Calculating magnification:
Ocular lens x objective lens = total magnification
Example:
Ocular (10x) x objective (40x) = 400x
As magnification increases resolution/(sharpness) decreases.

9. What’s my power?
To calculate the power of magnification, multiply the power of the ocular lens by the power of the objective.
What are the powers of magnification for each of the objectives we have on our microscopes?

10. Comparing Powers of Magnification
We can see better details with higher the powers of magnification, but we cannot see as much of the image.
Which of these images would be viewed at a higher power of magnification?

11. Check Yourself!
Why must specimens be thin for a compound light microscope?
Which microscope provides the highest possible magnification?
If the ocular lens is 10x and the objective lens is 10x then the total magnification is?
As magnification increases, resolution _______________

12. Check Yourself!
Why must specimens be thin for a compound light microscope? TO ALLOW LIGHT TO PASS THROUGH THE SPECIMEN
Which microscope provides the highest possible magnification?
If the ocular lens is 10x and the objective lens is 10x then the total magnification is?
As magnification increases, resolution _______________

13. Check Yourself!
Why must specimens be thin for a compound light microscope? TO ALLOW LIGHT TO PASS THROUGH THE SPECIMEN
Which microscope provides the highest possible magnification? TEM (TRANSMISSION ELECTRON)
If the ocular lens is 10x and the objective lens is 10x then the total magnification is?
As magnification increases, resolution _______________

14. Check Yourself!
Why must specimens be thin for a compound light microscope? TO ALLOW LIGHT TO PASS THROUGH THE SPECIMEN
Which microscope provides the highest possible magnification? TEM (TRANSMISSION ELECTRON)
If the ocular lens is 10x and the objective lens is 10x then the total magnification is? 10 X 10 = 100X
As magnification increases, resolution _______________

15. Check Yourself!
Why must specimens be thin for a compound light microscope? TO ALLOW LIGHT TO PASS THROUGH THE SPECIMEN
Which microscope provides the highest possible magnification? TEM (TRANSMISSION ELECTRON)
If the ocular lens is 10x and the objective lens is 10x then the total magnification is? 10 X 10 = 100X
As magnification increases, resolution _DECREASES_

16. Cheek Cells!